Protein crystals with large unit cells pose a challenge to structure determination by X-ray crystallography. Long crystal-to-detector distances are required to resolve reflections. Larger proteins also tend to pack more inefficiently - their crystals often have a high solvent content, and on average do not diffract as strongly as would crystals of a similar size but with smaller cells. In addition, as the scattered radiation is spread over many reflections, crystals with larger cells will tend to have relatively weak intensities. For all these reasons the high photon flux available at synchrotrons is particularly beneficial. We would be particularly interested in the possibility of visiting beam line 9-1, where the combination of the intense beam and long crystal-to-detector distance would be very helpful.